This project examines the early development of spatial analytic functioning in young children with focal brain injury. Spatial analysis refers to the ability to specify both the parts and the overall configuration of a visually presented pattern, and to understand how the parts are related to form an organized whole. It is an important basic spatial cognitive function. Studies of adults with localized brain injury suggest that spatial analytic functioning is affected differentially by injury to right and left posterior brain region. Injury to right posterior regions results in disorders of spatial integrative functioning, while injury to left posterior regions impairs the ability to define the parts of a form. Work from our laboratories has shown that differential patterns of specific spatial cognitive deficit are associated with early focal right hemisphere (RH) and left hemisphere (LH) injury. These studies demonstrate, at a very general level of analysis, that children with RH injury have difficulty with spatial integration. That is, while they appeared to be able to identify, or segment, the parts of spatial forms, they had difficulty organizing those parts into integrated spatial configurations. In contrast, children with LH injury appeared to have difficulty with encoding pattern detail. They tend to oversimplify spatial forms and fail to incorporate pattern detail. The two patterns we have observed in children are consistent with kinds of deficit observed among adults with similar injury. However, impairment in the child populations tends to be milder than that of adults, and children appear to be better able than adults to compensate for their deficits. This pattern of findings supports neither extreme view of the relation between brain and behavior in development. Findings of early specific deficit demonstrate that the brain is not equipotential for all functions, at least by the early preschool period, and show there are clearly constraints on the extent of neural and behavioral plasticity. On the other hand, early injury appears to result in less severe impairment and we continue to find evidence suggesting patterns of functional recovery with development. The major goals of this project are to extend these findings in two ways: First, to define more precisely the patterns of deficits associated with early injury to different brain regions, and, second, to examine longitudinal patterns of development for evidence of functional sparing. To accomplish these goals we have proposed a series of longitudinal studies which will accomplish three goals: (1) extend the set of spatial construction tasks used to test the children, (2) introduce a set of spatial perception tasks which will allow us to explore spatial analysis within a set of tasks that do not require the child to generate a spatial product, and (3) introduce a set of tasks which allow us to compare performance across the construction and perceptual domains.